Yes, the pension income is reported and you can do it two different ways in TurboTax.
1. Enter the foreign pension as a substitute 1099-R form:
Or (updated for TY 2020)
2. Enter the amount on Line 8 of Schedule 1, Form 1040
If you also paid foreign taxes on the pension, You can deduct under Deductions & Credits, Estimates and Other Taxes paid Foreign Taxes.
[edited 1/18/2020 | 5:59am pst]
Did you really mean line 21 of Form 1040? I had a look at my 2019 Form 1040, and line 21 is for "Amount of line 20 you want refunded to you." Or did you mean line 7a, "Other Income from Schedule 1"?